Self-supported sponge MnO2 nanotube monoliths (SMM) are synthesized via a hydrothermal method using commercial polyurethane foam as a sacrificial template. The SMM with its three-dimensional interconnected foam structure, macroporous channels, and mesoporous tube structure endow this novel material with a diversity of porous architectures and great promise for various applications involving sorbents, catalysts, ion exchange, and energy storage. As a proof of application, we have demonstrated that an SMM-based supercapacitor exhibits excellent capacitance behavior and rate capability.